Bonding plastic to plastic?

[mono]

I'm in the process of building a trickle (above water level of tank, after failed attempts at reliable overflow) filter, I've got all the levels sorted and it looks like it will work a treat, EXCEPT

because i'm above water level I'm draining water out of the bottom of the filter (a large acrylilic storage container) into the tank. I've drilled a couple of 19mm hole in the bottom of the side of the container and used some fittings to try and get a waterproof seal, but it leaks.

Does anybody have a non-toxic method of sealing this connection? I've tried silicone but it doesn't stick, I was thinking about superglue but that can't be good for fish!!

Thanks!!

 

[RogerMcAllen]

PVC glue bonds plastic to plastic well. I have used it in my pond, but I am not 100% sure if it is fish safe.

 

[justDIY]

holes, fittings ok...

do your fittings thread together, or are they just stuffed in the hole?

if it threads together, use a rubber o-ring on the "inside" part, that is the part in the water. slip the o-ring around over the hole, and then assemble your pieces together, make sure to compress the o-ring some but not to the point that it's distorted.

if your fitting is stuffed in the hole, no amount of glueing will help in my opinon, as any time you touch the fitting to take hose on or off, it will stress the glue and could cause a leak. If you really want to try glue, sand everything with some 60 grit sand paper (coarse), and then use something like JB Weld or Weld-On #16 - should make a water tight seal, but I don't know about how strong it will be.